1. Field of the Invention
The invention relates to a multi-layer module with constant characteristic impedance. Generally, such modules are made up of several layers of ceramic material, between which the conductor planes extend. These conductors may be signal lines, lines connected to ground or mass (which are subsequently referred to as ground lines) or lines to which an operating voltage is applied (which are subsequently referred to as voltage supply lines). The lines in the various layers are through-connected by so-called interconnecting vias extending through one or several layers.
2. Description of the Prior Art
One prior art structure as illustrated in FIG. 2, is a multi-layer module wherein signal line planes are arranged between a plane of ground lines and a plane of voltage supply lines. The conductors of two superposed signal line planes are arranged orthogonally to each other, to minimize the influence the lines exert on each other.
Another prior art structure wherein the voltage supply and signal lines are arranged in one plane is described in IBM TDB Vol. 20, No. 8, p. 3092, 1978. Three signal lines each are interleaved between two voltage supply lines. In the TDB article it is also pointed out that if several line planes are used, two lines corresponding to each other have to be diagonally displaced to minimize cross-sectional noise coupling.
The known arrangements described above have the disadvantage that they are unsuitable for high signal sequences (maximum switching speed of electronic components), because the characteristic impedances of the individual signal lines are of different magnitudes, so that the mismatching which is bound to occur with regard to the circuits connected to the multi-layer modules leads to reflections of different intensities, which in turn affect or preclude high-speed optimum signal transmission.